This invention is a method of treating cancer, both carcinomas and sarcomas, and viral infections, in particular HIV through the administration of a pharmaceutical composition containing a benzimidazole derivative. The composition is also claimed.
Cancers are the leading cause of death in animals and humans. The exact cause of cancer is not known, but links between certain activities such as smoking or exposure to carcinogens and the incidence of certain types of cancers and tumors has been shown by a number of researchers.
Many types of chemotherapeutic agents have been shown to be effective against cancers and tumor cells, but not all types of cancers and tumors respond to these agents. Unfortunately, many of these agents also destroy normal cells. The exact mechanism for the action of these chemotherapeutic agents are not always known.
Despite advances in the field of cancer treatment the leading therapies to date are surgery, radiation and chemotherapy. Chemotherapeutic approaches are said to fight cancers that are metastasized or ones that are particularly aggressive. Such cytocidal or cytostatic agents work best on cancers with large growth factors, i.e., ones whose cells are rapidly dividing. To date, hormones, in particular estrogen, progesterone and testosterone, and some antibiotics produced by a variety of microbes, alkylating agents, and anti-metabolites form the bulk of therapies available to oncologists. Ideally cytotoxic agents that have specificity for cancer and tumor cells while not affecting normal cells would be extremely desirable. Unfortunately, none have been found and instead agents which target especially rapidly dividing cells (both tumor and normal) have been used.
The development of materials that would target tumor cells due to some unique specificity for them would be a breakthrough. Alternatively, materials that were cytotoxic to tumor cells while exerting mild effects on normal cells would be desirable.
HIV and other viral infections are another leading cause of death. HIV is a disease in which a virus is replicated in the body which attacks the body""s immune system. The HW virus is not easily destroyed nor is there a good mechanism for keeping the host cells from replicating the virus. Herpes Simplex is another viral infection which is difficult, if not impossible, to cure. A method of treating these diseases and other viral infections is highly desirable. A material which would target the HIV virus and inhibit viral replication is highly desirable.
The benzimidazole derivatives used herein to treat cancer and/or viral infection have been used as fungicides and as antihelmetics.
A method of treating cancer, in particular, treating cancers in warm blooded animals and humans, comprising administering a therapeutically effective amount of a composition comprising a benzimidazole compound selected from the group consisting of: 
wherein X is hydrogen, halogen, alkyl of less than 7 carbon atoms or alkoxy of less than 7 carbon atoms; n is a positive integer of less than 4; Y is hydrogen, chlorine, nitro, methyl, ethyl or oxychloro; R is hydrogen, alkylaminocarbonyl wherein the alkyl group has from 3 to 6 carbon atoms, or an alkyl group of from 1 to 8 carbon atoms and R2 is 4-thiazolyl, NHCOOR1 wherein R1 is aliphatic hydrocarbon of less than 7 carbon atoms, and preferably an alkyl group of less than 7 carbon atoms is claimed. Preferably the compositions contain: 
wherein R is an alkyl of 1 through 8 carbon atoms and R2 is selected from the group consisting of 4-thiazolyl, NHCOOR1, wherein R1 is methyl, ethyl or isopropyl and the non-toxic, pharmaceutically acceptable acid salts with both organic and inorganic acids. The most preferred compounds are 2-(4-thiazolyl)benzimidazole, methyl-(butylcarbamoyl)-2-benzimidazolecarbamate and 2-methoxycarbonylamino-benzimidazole and those wherein Y is chloro.
In the present invention it has been discovered that the compounds described above are useful for the inhibition of HIV and the treatment of HIV infection and similar retrovirus infections. The present invention also provides methods for the treatment of HIV infection comprising administering to a host infected with HIV a pharmaceutically or therapeutically effective or acceptable amount of a compound as described above, particularly those wherein R is 4-thiazolyl.
The present invention also provides a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a therapeutically effective amount of a compound as described above.
These compositions have been discovered to inhibit the growth of cancer or other tumors in humans or animals and to induce apoptosis of cancer cells by administration of a therapeutically effective amount of the composition, preferably by administering a benzimidazole compound to the site of the cancer.
More specifically, this invention provides an anti-cancer composition comprising a pharmaceutical carrier and a benzimidazole derivative as defined herein along with a method for treating such cancers. These compositions can induce apoptosis in cancer cells.
These compositions are also effective against viruses and are used to treat viral infections and this invention provides a method of treating viral infections such as herpes, hepatitis, influenza and rhinoviruses.
As used herein, a xe2x80x9cpharmaceutically acceptablexe2x80x9d component is one that is suitable for use with humans and/or animals without undue adverse side effects (such as toxicity, irritation, and allergic response) commensurate with a reasonable benefit/risk ratio.
As used herein, the term xe2x80x9csafe and effective amountxe2x80x9d refers to the quantity of a component which is sufficient to yield a desired therapeutic response without undue adverse side effects (such as toxicity, irritation, or allergic response) commensurate with a reasonable benefit/risk ratio when used in the manner of this invention. By xe2x80x9ctherapeutically effective amountxe2x80x9d is meant an amount of a compound of the present invention effective to yield the desired therapeutic response. For example to inhibit HIV infection or treat the symptoms of infection in a host or an amount effective to delay the growth of or to cause a cancer, either a sarcoma or lymphoma, to shrink. The specific safe and effective amount or therapeutically effective amount will, vary with such factors as the particular condition being treated, the physical condition of the patient, the type of mammal being treated, the duration of the treatment, the nature of concurrent therapy (if any), and the specific formulations employed and the structure of the compounds or its derivatives.
As used herein, a xe2x80x9cpharmaceutical saltsxe2x80x9d is salt of the benzimidazole derivatives which are modified by making acid or base salts of the compounds. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids. Preferably the salts are made using an organic or inorganic acid. These preferred acid salts are chlorides, bromides, sulfates, nitrates, phosphates, sulfonates, formates, tartrates, maleates, malates, citrates, benzoates, salicylates, ascorbates, and the like.
As used herein, a xe2x80x9cpharmaceutical carrierxe2x80x9d is a pharmaceutically acceptable solvent, suspending agent or vehicle for delivering the benzimidazole derivatives to the animal or human. The carrier may be liquid or solid and is selected with the planned manner of administration in mind.
As used herein, xe2x80x9ccancerxe2x80x9d refers to all types of cancer or neoplasm or malignant tumors found in mammals, including carcinomas and sarcomas. Examples of cancer are cancer of the brain, breast, cervix, colon, head and neck, kidney, lung, non-small cell lung, melanoma, mesothelioma, ovary, sarcoma, stomach, uterus and Medulloblastoma.
As used herein, the xe2x80x9cbenzimidazole derivativesxe2x80x9d are the benzimidazoles, and their salts and also their prodrugs. The exact benzimidazoles are described in detail below. The preferred materials are the products sold under the names xe2x80x9cThiabendazole(copyright)xe2x80x9d, xe2x80x9cBenomyl(copyright)xe2x80x9d and xe2x80x9cCarbendazim(copyright)xe2x80x9d by BASF and Hoechst, DuPont and MSD-AgVet.
As used herein xe2x80x9cvirusesxe2x80x9d includes viruses which infect animals or mammals, including humans. Viruses includes retorviruses, HIV, influenza, polio viruses, herpes, herpes simplex, rhinoviruses, hepatitis, and the like.
The benzimidazole derivatives which are known for their antifungal activities. They are systemic fungicides used to prevent and eradicate fungi. The compounds have the following structure: 
wherein X is hydrogen, halogen, alkyl of less than 7 carbon atoms or alkoxy of less than 7 carbon atoms; n is a positive integer of less than 4; Y is hydrogen, chlorine, nitro, methyl, ethyl or oxychloro; R is hydrogen, alkylaminocarbonyl wherein the alkyl group has from 3 to 6 carbon atoms or an alkyl group having from 1 to 8 carbons, and R2 is 4-thiazolyl, NHCOOR1 wherein R1 is aliphatic hydrocarbon of less than 7 carbon atoms, and preferably and alkyl group of less than 7 carbon atoms. Preferably the compositions are: 
wherein R is an alkyl of 1 through 8 carbon atoms and R2 is selected from the group consisting of 4-thiazolyl, NHCOOR1, wherein R1 is methyl, ethyl or isopropyl and the non-toxic, pharmaceutically acceptable acid salts with both organic and inorganic acids.
The most preferred compounds are 2-(4-thiazolyl)benzimidazole, methyl-(butylcarbamoyl)-2-benzimidazolecarbamate and 2-methoxycarbonylamino-benzimidazole and the compounds wherein Y is chloro and X is hydrogen.
The benzimidazole compounds also include prodrugs. xe2x80x9cProdrugsxe2x80x9d are considered to be any covalently bonded carriers which release the active parent drug according to the formula of the benzimidazole derivatives described above in vivo when such prodrug is administered to a mammalian subject. Prodrugs of the benzimidazole compounds are prepared by modifying functional groups present in the compounds in such a way that the modifications are cleaved, either in routine manipulation or in vivo, to the parent compounds. Prodrugs include compounds wherein hydroxy, amine, or sulfhydryl groups are bonded to any group that, when administered to a mammalian subject, cleaves to form a free hydroxyl, amino, or sulfthydryl group, respectively. Examples of prodrugs include, but are not limited to, acetate, formate, or benzoate derivatives of alcohol and amine functional groups in the benzimidazole derivatives; phosphate esters, dimethylglycine esters, aminoalkylbenzyl esters, aminoalkyl esters and carboxyalkyl esters of alcohol and phenol functional groups in the benzimidazole derivatives; and the like.
The pharmaceutically acceptable salts of the benzimidazole derivatives include the conventional non-toxic salts or the quatemary ammonium salts of the benzimidazole derivatives formed, for example, from non-toxic inorganic or organic acids. For example, such conventional non-toxic salts include those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric and the like; and the salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic, 2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic, and the like.
The pharmaceutically acceptable salts of the present invention are synthesized from the benzimidazole derivatives which contain a basic or acidic moiety by conventional chemical methods. Generally, such salts are prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, nonaqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are preferred. Lists of suitable salts are found in Remington""s Pharmaceutical Sciences, 17th ed., Mack Publishing Company, Easton, Pa., 1985, p. 1418, the disclosure of which is hereby incorporated by reference. The disclosures of all of the references cited herein are hereby incorporated herein by reference in their entirety.
The benzimidazole derivatives are prepared in a number of ways well known to one skilled in the art of organic synthesis. The benzimidazole derivatives are synthesized using the methods described below, together with synthetic methods known in the art of synthetic organic chemistry, or variations thereon as appreciated by those skilled in the art. Preferred methods include but are not limited to those methods described below. Each of the references cited below are hereby incorporated herein by reference.
These compounds are prepared according to the method described in U.S. Pat. No. 3,738,995 issued to Adams et al, Jun. 12, 1973. The thiazolyl derivatives are prepared according to the method described in Brown et al., J. Am. Chem. Soc., 83 1764 (1961) and Grenda et al., J. Org. Chem., 30, 259 (1965).
The type of compound and the carrier and the amount will vary widely depending on the species of the warm blooded animal or human, body weight, and tumor being treated. The dosage administered will vary depending upon known factors, such as the pharmacodynamic characteristics of the particular agent and its mode and route of administration; the age, health and weight of the recipient; the nature and extent of the symptoms; the kind of concurrent treatment; the frequency of treatment; and the effect desired.
The benzimidazole is preferably micronized or powdered so that it is more easily dispersed and solubilized by the body. Processes for grinding or pulverizing drugs are well known in the art. For example, a hammer mill or similar milling device are used. The preferred particle size is less than about 100xcexc and preferably less than 50xcexc.
The dosage administered will vary depending upon known factors such as the pharmacodynamic characteristics of the particular active ingredient, and its mode and route of administration; age, sex, health, metabolic rate, absorptive efficiency and/or weight of the recipient; nature and extent of symptoms; kind of concurrent treatment, frequency of treatment; and the effect desired.
xe2x80x9ctumor growth inhibiting amountxe2x80x9d of the benzimidazole derivatives is that amount which is effective to inhibit or slow the growth of a tumor.
Dosage forms (compositions) suitable for internal administration contain from about 1.0 milligram to about 5000 milligrams of active ingredient per unit. In these pharmaceutical compositions, the active ingredient will ordinarily be present in an amount of about 0.5-95% by weight based on the total weight of the composition. Based on the body weight of the patent, the dosage may be administered in one or more doses several times per day or per week. Multiple dosage units may be required to achieve a therapeutically effective amount. For example, if the dosage form is 1000 mg, and the patient weighs 40 kg, one pill will provide a dose of 25 mg per kg for that patient. It will provide a dose of only 12.5 mg/kg for a 80 kg patient.
The compounds have shown dose responsiveness in vivo against viruses and cancers in mice at 500 mg/kg, 2500 mg/kg, 3500 mg/kg, 4000 mg/kg, 5000 mg/kg and 6000 mg/kg. Generally a dosage effective in mice translates to about {fraction (1/12)} of the dosage required in humans. By way of general guidance, for humans a dosage of as little as about 30 milligrams (mg) per kilogram (kg) of body weight and up to about 10000 mg per kg of body weight is suitable. Preferably from 50 mg/kg to about 5000 mg/kg of body weight is used. Most preferably the doses are between 100 mg/kg to about 3000 mg/kg of body weight. However, a dosage of between about 2 milligrams (mg) per kilogram (kg) of body weight to about 400 mg per kg of body weight is also suitable for some indications.
Intravenously, the most preferred doses may range from about 1 to about 1000 mg/kg/minute during a constant rate infusion. Benzimidazole derivatives may be administered in a single daily dose, or the total daily dosage may be administered in divided doses of two, three, or four times daily. The benzimidazole derivatives are given in one or more doses on a daily basis or from one to three times a week.
The benzimidazole derivatives may also be administered in intranasal form via topical use of suitable intranasal vehicles, or via transdermal routes, using those forms of transdermal skin patches well known to those of ordinary skill in that art. To be administered in the form of a transdermal delivery system, the dosage administration will, of course, be continuous rather than intermittant throughout the dosage regimen.
Generally, the dosage in man is lower than for small warm blooded mammals such as mice. A dosage unit may comprise a single compound or mixtures thereof with other compounds or other cancer inhibiting compounds or tumor growth inhibiting compounds or anti-viral compounds. The dosage unit can also comprise diluents, extenders, carriers and the like. The unit may be in solid or gel form such as pills, tablets, capsules and the like or in liquid form suitable for oral, rectal, topical, intravenous injection or parenteral administration or injection into or around the tumor.
The benzimidazole derivatives are typically mixed with a pharmaceutically acceptable carrier. This carrier can be a solid or liquid and the type is generally chosen based on the type of administration being used. The active agent can be coadministered in the form of a tablet or capsule, as an agglomerated powder or in a liquid form. Examples of suitable solid carriers include lactose, sucrose, gelatin and agar. Capsule or tablets are easily formulated and can be made easy to swallow or chew; other solid forms include granules, and bulk powders. Tablets may contain suitable binders, lubricants, diluents, disintegrating agents, coloring agents, flavoring agents, flow-inducing agents, and melting agents. Examples of suitable liquid dosage forms include solutions or suspensions in water, pharmaceutically acceptable fats and oils, alcohols or other organic solvents, including esters, emulsions, syrups or elixirs, suspensions, solutions and/or suspensions reconstituted from non-effervescent granules and effervescent preparations reconstituted from effervescent granules. Such liquid dosage forms may contain, for example, suitable solvents, preservatives, emulsifying agents, suspending agents, diluents, sweeteners, thickeners, and melting agents. Oral dosage forms optionally contain flavorants and coloring agents. Parenteral and intravenous forms would also include minerals and other materials to make them compatible with the type of injection or delivery system chosen.